Precision measuring instrument



W. E. SWARTOUT.

PRECISION MEASURING INSTRUMENT.

APPLICATION FILED JUNE 24. I921.

Patented. Aug. 29, 1922.

in. .l i V: rr sllldlal l WILLIAM E. SW'AR'IOUT, OF GHICAGQ, ILLINOIS.

ERECISION MEASURING INSTRUMENT.

emes.

To all whom. it may concern:

Be, it known that l, TVILLIAM E. SWART- OUT, a citizen of the United States, residing at Chicago, in the county of Cool: and State of'Illinois, have invented certain new and useful Improvements in Precision Measuring instruments, of which the following is a specification.

The present invention relates to precision measuring instruments.

The invention is illustrated and described in connection with a mechanics square and is useful in precision work where lines or surfaces are to be brought into precise right angular relation. The invention also contemplates a structure by means of which the degree of divergence from a right angle relation may be accurately indicated.

In its broader aspects the invention is useful in connection with angles other than right angles though perhaps it finds its greatest field of applicability in connection with squares. For this reason, the invention for the purpose of convenience is described in connection with squares.

An object of the present invention is to provide a precision measuring instrument which may be readily set to indicate a pre determined angle with. great accuracy.

A further object is to provide a precision instrument which will, with great accuracy, measure the divergence of two member from a predetermined angle.

A further object is to provide a device which may be used as an auxiliary to squares, as at present known and used, whereby to permit the use of said squares in work of very great refinement.

A further object is to provide micrometer mechanism which will clearly indicate small differences, which will be little subjectto wear and which, though sensitive in its action, presents very little likelihood of getting out of order.

Further objects will appear as the description proceeds.

Referring to the drawings- Figure 1 represents a square having an embodiment of the present invention applied thereto.

Figure 2 is aplan view of the mechanism shown in Figure 1.

Figure '3 is a view on an enlarged scale of the micrometer mechanism shown in Figure 1, parts being removed to show the internal mechanism.

Specification of Letters Patent.

Applicatien filed. June 24, .92 Serial No, 479,998.

Patented Aug. 29. 19232.

Figure is a crosssectional view taken along the line 4.4% of Figure 1.

ihe numeral 10 indicates a square such as may be used by artisans in setting up their work. Said square '10 is provided with a leg 11 and a leg 12, the outer edges of which will lie more or less closely at right angles to one another. Mounted on the outer edge of the leg 12 is a bifurcated supporting vertically from the supporting memberl3,

which supporting member 17 will be grooved, as indicated at 18 for the reception of a pin 19 extending laterally on both sides of the straight edged member 14;. The

pin 19 rides loosely in the grooves 18 in the supporting member 17. The supporting member 17 merely serves the purpose of preventing the straight edged member 14 from moving too far from the leg 12.

Suitably mounted upon the leg 12 of the square 10 is a micrometer device 20. Said micrometer device 20 may be slotted for the reception of the leg 12 and may be held in position on said leg 12 by means of the set screws 2l-2l. The device 20 has a longitudinally movable yieldable member 22 provided with an adjustable contact point 23. The contact point 23 is adapted to engage the inside surface 23 of the straight edged member 14. The surface 23', the center line of the pin 18 andthe center line of pin 15 should preferably lie in a single plane.

Referring now to Figure 3, it will be noted that the device 20 is provided with a pointer 24c, having a notch 25 constituting a fulcrum seat for a knife edged fulcrum 26, which knife edge constitutes the axis of rotation of the pointer 24. The numeral 27 indicates a scale adjustably mounted to have a movement of rotation about said axis. Said scale 27 may be held in adjusted positionby means of the thumb screw 28, which isv threaded into member 20 and which rides in a slot 29 in the pivoted supporting member for scale 27. Fulcrumed at a point adjacent to the zone of the path of movement of the outer end of the pointer 24 is an operating The 70 lies on the Zero mark.

member 80. The left hand end portion of the member 30 is notched, as indicated at 31. The pointer 2a is also notched at the point 32 lying near to the fulcrum 26 but between said fulcrum and the outer end of the pointer 24. A fulcrum member 33 is provided with a pair of knife edges at its opposite ends, which knife edges engage with the notches 31 and 32 in the operating member 30 and pointer 24 respectively. Said fulcrum member '33 communicates movement from the operating member 30 to the pointer 24c, and should normally lie with its center line tangential to the circleof movement of the seat of the notch 31. A spring 34: is provided whichbiases the member 30 and the pointer 24: to positions in proximity to one another. A hardened steel fulcrum member 35 is provided at the right hand. end of the device 20 for providing a fulcrum seat for member 30. l i

The longitudinally movable member 22 is provided" with a head 36, notched as indicated at 37. The operating member 30 is notched as indicated bythe numeral Said notches 37v and 38 provide fulcrum seats for a link member 39, which is provided with knife edges at bothends thereof for action in said fulcrum seats 37 and 88..

The head member 36 may be provided with a stud L0, which provides an abutment for adjusting; the spring ll. The tension of the spring all maybe adjusted by means of the screw' l2. Position of the member 35 may be adjusted by means of the screw 43.

A mode of operation of the above described embodiment of the present inven ion is substantially as follows:

The instrument will be adjusted. by test,

so that the edge 16 will lie at perfect right angles'to the under side of leg 11. The scale 27 will be adjusted so that the pointer Thereafter when. it is desired. to. test the angularity between anyv two members, the leg'll of the square will be placed in contact with one of said members and the edge 16 of the member 14s will be placed. incontact with the other of said members. If, the member 14 under these circumstancesmakes an angle with the leg 11 which is more than a rightv angle, the spring Set will urge the pointer 24linto proximity with the operating member 30 moving the pointer 24s from the zero mark on the scale, The scale 27 will he graduated, whereby to indicate at once the deviation from' the true right angular relation. If,

on the other hand, the member i l under snnllar c rcumstances, assumes an angular relation withthe leg 11 which is less than a right angle, the' contact point 23 will be moved n a right hand directlon, as viewed in Figure 3' resulting in the raising of pointer 24;.

The pin 15 will be so located that gravity p emes will carry the top of member 14: away from member 20. Therefore, the top portion of straight edgedv member l l will come into contact with the work first. As the instrument is moved toward the work it finally comes to a solid stop at the lower end. Then if the angle between the straight edge 16 and the loweredge of member 12 varies from 90 degrees, the indicator 24: will correspondingly vary fromthe'zero mark.

The link 2-39 and operating member 30 constitute two arms of a toggle mechanism. lllt ment of the member 22 in a right hand direction will have the effect of increasing.

the angular relation between the two arms 30 and 39 of the toggle, whereby the operating member 30 will be moved in a clockwise direction. Preferably the angle be tween the plane passing through the operating knife-edges of the link 39 and'the line of movementof the member 22, should be relatively small. This angle-should-be chosen of a value such that the sine thereof varies with substantial uniformity with variations inv said angle. In practice it has knife edges of the link 39 and the line of movement of member the neighborhood of 10 degrees.

Movement of operating member 30 in a clockwise direction will communicate mo 'tron tothe pointer 34 through the link 33,

which is in fulcruming relation betweensaid member 30 and'said pointer 24. Inasmuch as the link 32 applies force to the pointer 24 close to the j'fulerum point thereof and is applied to the operating member 30 at a point I near the outer end thereof, the advantage will be 1 oduced that small increments of movement of the member 22 will result in.

large changes in the position of the pointer 24 relative to the scale 27.

It will be noted that no pivots are pro-' vided in the micrometer mechanism 20, the

various members of said mechanism having whereby wear will be inappreciable andat the same time friction and lost motion Will.

be reduced to a vminimum.

The spring ll has the effect balancing; the spring S t, and inasmuch as it is readily adjustable by means of the screw 4-2, the spring tension of the device may be readily "changed; 1

Inasmuch as the sine of the angle between theplaneof the operating edges of the link 39 and the line of movement of the member varies substantially uniformly with increments of movement of said member 22,. the instrument will give substantially correct readings. regardless of the operating position of the scale 27 within the limits in which a precision instrument of-thisna- 22 may be nv of counterbeen determined that the angular relation between the plane connecting the operating ensa ture is meant to perform. Any errors in hgrent in the mechanism will be inappre'cia 1e.

It will be obvious, of course, that the scale 27 may be kept in fixed relation to the member 20, all adjustments being accomplished by means of adjustable contact point 28. In this case the scale 27 may be graduated to measure changes in the position of member 22 with the greatest possible degree of accuracy.

One embodiment-of the present invention has been described in detail. Many modifications will occur to those skilled in the art. It is intended in this patent to cover all such modifications that come within the scope of the invention as defined by the appended claims.

lVhat I claim as new and desire to secure by Letters Patent in the United States, is:

1. An instrument having two side edges angularly placed relative to one another, a straight edged member fulcrumed on said instrument adj acentto one of said edges, and measuring means mounted on said instrument for accurately indicating the angularity between said straight edged member and the other of said edges, said measuring means being provided with a yielding member abutting said straight edged member, said measuring means being provided with means for visually indicating said angularity.

2. In combination, a square, an auxiliary straight edge, means for fulcruming said straight edge to occupy a position along one leg of said square and a measuring device on said leg having a yielding member abutting said straight edge, said measuring device being provided with a member for giving a visual indication of the position of said abutting member.

3. In combination, a square, an auxiliary straight edge, means for fulcruming said straight edge to occupy a position along one leg of said square and a measuring device on said leg, said measuring device having a yieldable member for abutting said straight edge to oppose pivotal movement of same in one direction and means for multiplying movement of said yieldable member for indicating purposes.

4. A micrometer, comprising an indicator biased to a predetermined position, an operating member therefor, said operating member being an extended member lying through out its length in proximity to the biased position of said indicator, said pointerand said member being fulcrumed at unadjacent ends and a fulcruming element mounted between adjacent end portions of said pointer and said member.

5. A micrometer, comprising an indicator biased to a predetermined position, an oper ating member therefor, said operating memher being an extended member lying throughout its length in proximity to the biased position of said indicator, said indicator and said. member being fulcrumed at unadjacent ends, a fulcruming element mounted between adjacent end portions ofsaid pointer and saidmember and spring means for biasing said pointerto a position in proximity to said member.

In combination, a rotatable indicator fulcrumed at a point near one of its ends, an operating member fulcrumed at a point adjacent to the zone marking the path of movement of the other end portion of said indicator, fulcruming means for communicating motion from said member to said pointer, located to engage said pointer at a point near its axis of rotation and to engage said member at a point distant from its fulcrum point.

'7. In combination, a rotatable pointer fulcrumed at a point near one of its ends, an operating member fulcrumed at a point adjacent to the zone marking the path of movement of the other end portion of said pointer, fulcruming means for communicating motion from said member to said pointer, located to engage said pointer at a point near its aXis of rotation and to engage said member at a point distant from its fulcrum point, a movable member and a second fulcruming member for communicating motion from said longitudinally movable member to sai d operating member.

8. A micrometer, comprising a movable member, a fulcrumed member, a link for communicating movement from said first mentioned member to rotate said second mentioned member about its fulcrum point, said link having a range of movement with in a relatively small angle with reference to the line of movement of said first mentioned member and a pointer controlled by said fulcrumed member. 1

9. Micrometer mechanism, comprising a movable member. an indicator, an operating member for said indicator fulcrumed for rotary movement, a link device between said first mentioned member and said operating member, having knife edge fulcruming engagement with said members, said device being located to operate in a range of angularity relative to the line of movement of said longitudinally movable member in which the sine of the angle varies closely in proportion to the angle.

10. Micrometer mechanism, comprising an indicator and an operating member therefor and a device for moving said operating member, said member and said device forming a toggle joint, of which said operating member has a relatively fixed fulcrum point, means whose position is to be indicated, said device being fulcrumed between said means and said operating member.

11. Micrometer mechanism, comprising an operating member and a device for moving same, said member and said device forming a toggle joint, of which said operating member has a relatively fixed fulcrum point, means whose position is to be indicated said devicebeing fulcrumed between said means and said operating member and means "for multiplying the movement of said operating member comprising a fulcrumed pointer and a double knife edged link between one end of said operating member and a part of said pointer near the fulcrum point thereof.

12. In combination, a square, a straight edged member fulcrumed thereon to occupy a position adjacent to one leg of said square, and a micrometer mechanism secured to'said lee said micrometer mechanism havin a e I vieldable member for-engag ng said straight edged member and indicating means for givmg visual indications of minute differences in the position of said yieldable member. 18'. A micrometer mechanism, comprising a toggle mechanism of the other arm whereby to-vary arm having an extension, a fulcrumed'ind-icater and means for communicating motion iron said extension to said-indicator;

Signed at Chicago, Illinois, this 16th day of-Jnne, 19

which one arm has a relatively fixed. abutment, means for moving the angularity between said arms, said first mentioned 21. W LLIAM SWARTOUT. r 

